The parameter space of galaxy formation

The parameter space of galaxy formation

Semi-analytic models are a powerful tool for studying the formation of galaxies. However, these models inevitably involve a significant number of poorly constrained parameters that must be adjusted to provide an acceptable match to the observed Universe. In this paper, we set out to quantify the degree to which observational data sets can constrain the model parameters. By revealing degeneracie...

formation and evolution of regional organizations: the case study of the economic cooperation organization (eco)

abstract because of the many geopolitical, geo economical and geo strategically potentials and communicational capabilities of eco region, members can expand the convergence and the integration in base of this organization that have important impact on members development and expanding peace in international and regional level. based on quality analyzing of library findings and experts interv...

Single parameter galaxy classification: The Principal Curve through the multi-dimensional space of galaxy properties

We propose to describe the variety of galaxies from the Sloan Digital Sky Survey (SDSS) by using only one affine parameter. To this aim, we construct the Principal Curve (P-curve) passing through the spine of the data point cloud, considering the eigenspace derived from Principal Component Analysis (PCA) of morphological, physical and photometric galaxy properties. Thus, galaxies can be labeled...

Parameter Tests Within Cosmological Simulations of Galaxy Formation

Numerical simulations of galaxy formation require a number of parameters. Some of these are intrinsic to the numerical integration scheme (e.g. the timestep), while others describe the physical model (e.g. the gas metallicity). In this paper, we present results of a systematic exploration of the effects of varying a subset of these parameters on simulations of galaxy formation. We use N–body an...

Formation of the Galaxy